'Inner peace' or peace of mind is a colloquialism that refers to a state of being mentally or spiritually at peace, with enough knowledge and understanding to keep onself strong in the face of discord or stress. Being "at peace" is considered by many to be healthy (homeostasis) the opposite of being stressed or anxious. Peace of mind is generally associated with bliss and happiness. Many religionists believe that it isn't possible (or at least very difficult) to achieve true inner peace without divine intervention of some form or another.

Peace of mind, serenity, and calmness are descriptions of a disposition free from the effects of stress. In some cultures, inner peace is considered a state of consciousness that may be cultivated by various forms of training, such as prayer, meditation, T'ai Chi Ch'uan or yoga, for example. Many spiritual practices refer to this peace as an experience of knowing oneself.